The Universal Mobile Telecommunications System (UMTS) technology was developed from GSM (2G), GPRS and EDGE (2.5G) technologies.

Global System for Mobile Communications (originally Groupe Spécial Mobile) was launched as a world standard and it was used by more than 3 million people in more than 212 countries and territories. Its ubiquity made the international roaming very common among the mobile telephony operators, which allows the subscribers to use their telephones in different parts of the world. GSM differs from its predecessor technologies since the signaling and the channels are digital and, thus, it is considered a technology of second generation (2G).

After its launching, new versions of the norm were created, retro-compatible with the original of the GSM telephones. The module 97 of the norm adds abilities of data packets, through General Packet Radio Service (GPRS) technology. The ’99 release presents more data transmission speed by using Enhanced Data Rates for GSM Evolution (EDGE). GPRS and EDGE technologies have been called “2.5 G”. Many services providers evolved to 2.5G networks before entering the third generation. The actualization to the 2.5G technologies that allowed the greater data transmission rate presented less costs and an easier deployment that the evolution to 3G technologies. Additionally, the evolution from 2.5G to 3G is easier and more natural.

The 2.5G generation offers extended characteristics, since it has more abilities and services tan the 2G systems. In this generation, one can find technologies like General Packet Radio System (GPRS), High Speed Circuit Switched Data (HSCSD), Enhanced Data Rates for Global Evolution (EDGE), IS-136 and IS-95Bm, among others.

The third generation (3G) is characterized for bringing voice and data convergence and increment transmission rate. In other words, it is suitable for multimedia applications and transmissions of data at high rate. The protocols employed in the 3G systems support high speeds of information and are focused on applications beyond the voice, like audio, video on movement, videoconference and broadband access to the internet. The 3G systems reach speeds over 384 kbps, allowing total mobility among the users, traveling at 120 kilometers per hour in exterior environments. It also reaches a maximum speed of 2Mbps, allowing a limited mobility to users, walking less than 10 kilometers per hour in stationary environments of short reach or in interiors.

Universal Mobile Telecommunications System (UMTS)

The UMTS technology was developed by the 3GPP group, taking as a basis its predecessor GPRS (and EDGE). UMTS is a member of the global IMT-2000 family of the mobile communication system of third generation of the ITU (International Telecommunications Union), IMT-2000 is a norm of standardization of 3G mobile technologies. In it, the requisites that a technology must possess to be considered third generation are detailed.

UMTS is the favorite platform for services and applications with high utilization rates. In the last 20 years, UMTS has been object of intense efforts of investigations and development in the whole world and it has the support of numerous and important manufacturers and operators of telecommunication.

UMTS is based on preexistent wireless and satellite technologies, providing incresed capacity, data transmission possibilities and a spectrum of services much more wide, using an innovative program of radio access and an improved core network.

The following objectives are the ones from which the UMTS standard was developed:

To offer a wide spectrum of services of voice, data and multimedia for a dynamic environment.

Personal and services mobility.

Ability to transmit synchronically and asymmetrically.

Data rates of up to 2Mbps.

Commutation of circuits and packets.

Optimization of the spectrums use.

Simultaneous services, dynamic assignation of bandwidth.

Simultaneous connections support (voice and data).

Standardized interfaces.

International roaming between operators.

From these objectives, the 3GPP group has consolidated the standard GSM/GPRS and it constructed the new generation. With such goal, a new radio interface was created: UMTS Terrestrial Radio Access Network (UTRAN). Also, the network was logically divided into two groups: Domains (Entity groups) and Layers (Protocols groups).

The physical architecture of UMTS networks is similar to the GPRS architecture, but with some naming differences.

3GPP group

The Third Generation Partnership Project, known as 3GPP, is an agreement of collaboration between different standardization organisms for the development and evolution of technical specifications of mobile standards.This forum was constructed in December 1998, and it originates as the meeting point between the different entities and standardization organisms which had presented a similar proposal based on Wideband Code Division Multiple Access (WCDMA) technologies, during the process of selection of the IMT-2000 standards (by the ITU). After some time, several tasks were added: The development and maintenance of GSM/GPRS/EDGE standards and radio access technologies; the evolution of the mobile system (Core and Access); and the development of an IMS technology (IP Multimedia Subsystem) independent of the access technology.

In practice, the 3GPP recommendations are usually adopted and considered by most operators and mobile manufacturers.